- use or planned use (for the duration of the study, 48 weeks) of rifampicin, St. John´s wort and drugs that are metabolized via the cytochrome P450 system with a narrow therapeutic PK-range such as astemizole, terfenadine, cisapride, pimozide, chinidin, bepridil, triazolam, midazolam, ergotamine, dihydroergotamin, ergometrine, methyl-ergometrine. FOR OTHER COMEDICATIONS please consult with the SPC of Raltegravir (Isentress®), Atazanavir (Reyataz®), Ritonavir (Norvir®), your hospital pharmacist, www.hiv-drug-interactions.org or the principal investigator in case of uncertainty.